Militants stormed the American University of Afghanistan in Kabul on Wednesday, carrying on an hourslong siege that ended with at least 13 people dead and dozens more injured.

Wakil Kohsar / AFP / Getty Images

Afghan security personnel stand guard near the site of the explosion that targeted the elite American University of Afghanistan in Kabul.

The attack began with a large explosion Wednesday evening near the campus, followed by gunfire. Several hours later, before dawn Thursday, the siege had ended.

Kabul police chief Abdul Rahman Rahimi said seven students, three police officers and two security guards were killed in the attack, according to Reuters. 35 students and nine police officers were also injured in the attack, Rahimi said Thursday. He added that 750 students were evacuated from the building.

The two militants were shot dead by police, nearly 10 hours after the assault started. Initially conflicting reports of the attackers added to the confusion, as hundreds of students desperately tweeted or posted on social media as the attack unfolded.

There was no immediate claim of responsibility.

Terrified students barricaded themselves in classrooms as militants stormed the campus, while others jumped from the second story to escape.

Rahmat Gul / AP

A senior Afghan official told Reuters that elite forces surrounded the university compound and then worked their way inside during the siege. Police described the attack to the BBC as "complex".

One journalist based in Kabul tweeted that students had been held inside the university, as well as what initially appeared to be several attackers.